Steering Column Pin Restraint Without Screw Shaft Extension
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Solution Overview
Problem
Existing steering devices face issues where the steering column can fall off due to the nut not stopping at a predetermined position, leading to a longer screw shaft length when a protrusion is used to prevent this, which compromises the stability.
Innovation Solution
A steering device design that incorporates a pin extending in a second direction intersecting the first direction, abutting on a projection or frame portion of a second steering column, and utilizing actuator devices to enhance attachment rigidity, preventing the steering column from falling off without increasing the overall length of the screw shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protrusion is provided at the tip of the screw shaft to prevent the nut from coming off, then the steering column falling off is prevented, but the overall length of the screw shaft becomes long
Solution Approach 1:
The patent transitions from a axial dimension solution (protrusion at the tip of screw shaft) to a radial dimension solution (protrusion on the side of the nut). By moving the restriction mechanism to the radial direction, the axial length of the screw shaft is shortened while still preventing the nut from coming off.
Solution Approach 2:
The patent introduces an intermediary element (the side protrusion on the nut) that mediates between the screw shaft and the steering column. This intermediary protrusion on the nut interacts with the screw shaft to prevent coming off, eliminating the need for a long axial protrusion on the screw shaft itself.
2Length of moving object
If the protrusion is thinned to shorten the screw shaft length, then the overall length is reduced, but the protrusion deforms during abutment and cannot restrict the nut movement
Solution Approach 1:
The patent applies local quality by concentrating the restriction function in a specific localized protrusion on the side of the nut, rather than relying on the axial length of the screw shaft. This localized protrusion provides sufficient restriction with minimal material, avoiding deformation while maintaining effectiveness.
3Manufacturing precision
If the axial position of the second steering column is controlled by the nut abutting on the screw shaft tip, then the position is determined, but the steering column may fall off when the motor fails
Solution Approach 1:
The patent implements preliminary action by providing the protrusion on the side of the nut in advance, before any failure can occur. This pre-positioned protrusion serves as a fail-safe mechanism that will automatically prevent the steering column from falling off if the motor fails or the control system malfunctions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design effectively prevents steering column detachment by improving attachment rigidity, ensuring stability without elongating the screw shaft, thus enhancing the reliability of the steering mechanism.
Implementation Method 1
The actuator device includes a ball screw having a screw shaft and a nut... When the motor is operated and rotated, the screw shaft rotates, and the nut moves in the axial direction relative to the screw shaft
Implementation Method 2
the actuator device includes a ball screw having a screw shaft and a nut, and a motor
Implementation Method 3
a protrusion having a diameter larger than that of a male threaded portion of the threaded shaft and capable of abutting on the nut is provided at the tip of the threaded shaft. When the nut abuts on the protrusion, the rotation of the nut is stopped
Data Source
AI summary
A steering device includes a first steering column arranged outside a steering shaft, and a second steering column arranged outside the first steering column and movable relative to the first steering column in a first direction. The first steering column includes a pin extending in a second direction intersecting the first direction. The second steering column includes a projection arranged on one side in the first direction of the pin and capable of abutting on the pin to prevent movement of the first steering column.